Sir Gawain was the nephew of King Arthur, king of Britannia and later Space Britain, and the son of Morgause and King Lot. He became a Knight of the Round Table at a young age thanks to his prowess and chivalry. He had the unnatural ability to become empowered by sunlight, giving him great strength against evil.
Sir Gawain wears leather armour, thinner than the suits of armour most knights wear, and over it is a pale green tabard with white checkers. His tabard seems almost robe-like, extending right down to the floor and is much thicker than the others'. His hair is muddy blonde and very untidy, looking like he may have cut it himself when it got in his eyes too much. In some way he actually looks quite like King Arthur, who is his uncle[Pan 1].
Gawain is quite gullible, believing in exaggarated tales even when they're cast into doubt[Pan 1].